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Journal of Hazardous Materials Oct 2023In this study, we developed a colorimetric ozone passive sampler (OPS) incorporating o-dianisidine, a redox dye, into a polydimethylsiloxane sheet. The reaction between...
In this study, we developed a colorimetric ozone passive sampler (OPS) incorporating o-dianisidine, a redox dye, into a polydimethylsiloxane sheet. The reaction between ozone (O) and o-dianisidine result in a visible yellowish color change. Unlike previous passive methods that rely on nitrate extraction or the color disappearance of indigotrisulfonate, the OPS offered improved recognition of average O exposure. To optimize OPS based on time-weighted average (TWA), we extracted and quantified the amount of reacted o-dianisidine after exposing OPS to O by varying concentrations (0-200 ppb) within 8 h. Colorimetric changes of OPS were further analyzed by capturing images, and the effective absorbance of blue scale showed the best fit (EA, R =0.997). OPS validation on visual detection assessed by six parameters: limit of detection, limit of quantification, reproducibility, sampling rate, selectivity to interfering gases, and sensitivity to environmental factors. To enhance visibility, the OPS was assembled with coloration exposure guidelines, and a smartphone app was developed to quantify average O exposures. We further conducted field tests that showed the significant disparity between O concentrations and personal O exposures, which is considered more crucial for assessing health risks. The OPS was optimized to monitor O exposure levels and raise awareness among workers and occupants regarding invisible indoor hazards.
Topics: Humans; Colorimetry; Dianisidine; Reproducibility of Results; Levonorgestrel; Ozone
PubMed: 37703734
DOI: 10.1016/j.jhazmat.2023.132510 -
The Journal of Biological Chemistry Dec 2023Prolyl hydroxylase domain (PHD)-containing enzyme 3 (PHD3) belongs to the Caenorhabditis elegans gene egl-9 family of prolyl hydroxylases. PHD3 catalyzes proline...
Prolyl hydroxylase domain (PHD)-containing enzyme 3 (PHD3) belongs to the Caenorhabditis elegans gene egl-9 family of prolyl hydroxylases. PHD3 catalyzes proline hydroxylation of hypoxia-inducible factor α (HIF-α) and promotes HIF-α proteasomal degradation through coordination with the pVHL complex under normoxic conditions. However, the relationship between PHD3 and the hypoxic response is not well understood. In this study, we used quantitative real-time PCR assay and O-dianisidine staining to characterize the hypoxic response in zebrafish deficient in phd3. We found that the hypoxia-responsive genes are upregulated and the number of erythrocytes was increased in phd3-null zebrafish compared with their wild-type siblings. On the other hand, we show overexpression of phd3 suppresses HIF-transcriptional activation. In addition, we demonstrate phd3 promotes polyubiquitination of zebrafish hif-1/2α proteins, leading to their proteasomal degradation. Finally, we found that compared with wild-type zebrafish, phd3-null zebrafish are more resistant to hypoxia treatment. Therefore, we conclude phd3 has a role in hypoxia tolerance. These results highlight the importance of modulation of the hypoxia signaling pathway by phd3 in hypoxia adaptation.
Topics: Animals; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Inducible Factor-Proline Dioxygenases; Procollagen-Proline Dioxygenase; Proline; Zebrafish; Zebrafish Proteins; Gene Deletion; Oxygen
PubMed: 37923141
DOI: 10.1016/j.jbc.2023.105420 -
Veterinary Sciences Oct 2023Ceruloplasmin (Cp) assessment in biological samples exploits the oxidase activity of this enzyme against several substrates, such as -phenylenediamine (-P), -dianisidine...
Ceruloplasmin (Cp) assessment in biological samples exploits the oxidase activity of this enzyme against several substrates, such as -phenylenediamine (-P), -dianisidine (-D) and, most recently, ammonium iron(II) sulfate (AIS). Once developed in humans, these assays are often used in veterinary medicine without appropriately optimizing in the animal species of interest. In this study, two assays using AIS and -D as substrates have been compared and validated for Cp oxidase activity assessment in horse's plasma. The optimization of the assays was performed mainly by varying the buffer pH as well as the buffer and the substrate molar concentration. Under the best analytical conditions obtained, the horse blood serum samples were treated with sodium azide, a potent Cp inhibitor. In the -D assay, 500 µM sodium azide treatment completely inhibits the enzymatic activity of Cp, whereas, using the AIS assay, a residual analytical signal was still present even at the highest (2000 µM) sodium azide concentration. Even though the analytical values obtained from these methods are well correlated, the enzymatic activity values significantly differ when expressed in Units L. A disagreement between these assays has also been detected with the Bland-Altman plot, showing a progressive discrepancy between methods with increasing analytical values.
PubMed: 37888575
DOI: 10.3390/vetsci10100623 -
Bio-protocol Jul 2023Myeloperoxidase (MPO) is an enzyme contained in lysosomal azurophilic granules of neutrophils. MPO activity has been shown to correlate with the number of neutrophils in...
Myeloperoxidase (MPO) is an enzyme contained in lysosomal azurophilic granules of neutrophils. MPO activity has been shown to correlate with the number of neutrophils in histological sections of the gastrointestinal tract and is therefore accepted as a biomarker of neutrophil invasion in the gut. This protocol describes an easy, cost-effective kinetic colorimetric assay to quantify myeloperoxidase activity in intestinal tissue samples. It is explained using tissue collected in mice but can also be used for other laboratory animals. In a first step, tissue specimens are homogenized using a phosphate buffer containing 0.5% hexadecyltrimethylammonium bromide (HTAB), which extracts MPO from neutrophils. The obtained supernatant is added to a reagent solution containing o-dianisidine dihydrochloride, which is a peroxidase substrate. Finally, the change in absorption is measured via spectrophotometry and converted to a standardized unit of enzyme activity. The assay is illustrated and compared to a commercially available enzyme-linked immunoassay (ELISA), demonstrating that MPO activity does not necessarily correlate with MPO protein expression in tissue samples. Key features Optimized for use in mice and rats but can also be used for samples of other species. Measures enzymatic activity instead of mRNA or protein expression. Requires a spectrophotometer. Can be performed in duplo using 10 mg of (dry-blotted) gut tissue or more. Graphical overview.
PubMed: 37456337
DOI: 10.21769/BioProtoc.4758 -
Molecules (Basel, Switzerland) Dec 2023Porous covalent organic frameworks (COFs) have been widely used for the efficient removal of iodine from solution due to their abundance of electron-rich sites. In this...
Porous covalent organic frameworks (COFs) have been widely used for the efficient removal of iodine from solution due to their abundance of electron-rich sites. In this study, two kinds of ketoenamine-based COFs, TpBD-(OMe) and TpBD-Me, are successfully synthesized via Schiff base reaction under solvothermal conditions using 1, 3, 5-triformylphoroglucinol as aldehyde monomer, o-tolidine and o-dianisidine as amino monomers. The ability of TpBD-(OMe) and TpBD-Me to adsorb iodine in cyclohexane or aqueous solutions has been quantitatively analyzed and interpreted in terms of adsorption sites. TpBD-Me possesses two adsorption sites, -NH- and -C=O, and exhibits an adsorption capacity of 681.67 mg/g in cyclohexane, with an initial adsorption rate of 0.6 g/mol/min with respect to COF unit cell. The adsorption capacity of TpBD-(OMe) can be as high as 728.77 mg/g, and the initial adsorption rate of TpBD-(OMe) can reach 1.2 g/mol/min in the presence of oxygen atoms between the methyl group and the benzene ring. Compared with TpBD-Me, the higher adsorption capacity and adsorption rate of TpBD-(OMe) towards iodine are not only reflected in organic solvents, but also in aqueous solutions. It is proven through X-ray photoelectron spectroscopy and Raman spectroscopy that iodine exists in the form of I, I, and I within TpBD-(OMe) and TpBD-Me after adsorption. This work not only expands the application of COFs in the field of iodine adsorption, but also provides research ideas and important an experimental basis for the optimization of iodine adsorption sites.
PubMed: 38138639
DOI: 10.3390/molecules28248151